Scroll down this page to find definitions of some of the most common terminology used when referring to home comfort systems, or click on any of the links throughout the site to return to this page.

AFUE% -

Annual Fuel Utilization Efficiency. A measure of a furnace's heating efficiency. The higher the AFUE%, the more efficient the product. The government's established minimum AFUE rating for furnaces is 78%.

The portion of the central air conditioning or
heat pump system that moves heated or cooled air throughout a home's ductwork. In some systems a furnace handles this function.

Balance Point -

An outdoor temperature, usually between 30° F and 45° F, at which a heat pump's output exactly equals the heating needs of the home. Below the balance point, supplementary electric resistance heat is needed to maintain indoor comfort.

Btu -

British thermal unit. The amount of heat required to raise the temperature of one pound of water (about one pint) by one degree F.

The pump that moves the refrigerant from the indoor evaporator coil to the outdoor condensing unit and back to the evaporator. The compressor functions as the heart of the system, because it circulates the refrigerant in a loop.

Heating Seasonal Performance Factor. A measure of a heat pump's heating efficiency. The higher the HSPF, the more efficient the product. There is no government established minimum HSPF rating for heat pumps.

Seasonal Energy Efficiency Ratio. A measure of an air conditioner's cooling efficiency.
The higher the SEER, the more efficient the product. The government's established minimum SEER rating for air
conditioners manufactured after January 2006 is 13.